Dorikka's comment notwithstanding, there are several Esperanto speakers here on LW, including yours truly.

I largely agree with Vladimir_M on the value of learning languages from a purely instrumental point of view -- except of course it depends on how easily you can do it. For me, it's probably my single greatest ability, so the opportunity cost is low. Also, competence in more than one language has status-signaling value beyond its practical uses. (This is true particularly in the United States, where knowledge of foreign languages is considered an esoteric skill.) And quite frankly, I find it to be an enjoyable hobby.